Rationale and Research Questions

Climate change is anticipated to bring about significant repercussions for marine life, including declining pH and oxygen, rising temperatures, and shifts in current patterns, affecting a diverse array of marine organisms across phylogenetic groups at both physiological and ecological levels. Cephalopods, constituting a substantial portion of the global mollusk biomass, play pivotal roles in marine food webs, offer essential ecosystem services, and possess significant economic value. Research indicates that cephalopods are susceptible to the impact of climate change, with squids particularly notable for their importance in human consumption, accounting for up to 70% of the cephalopod biomass harvested.

While most cephalopods are believed to be constrained by physiological and locomotive factors, hindering their presence in shallow, highly fluctuating, euryhaline environments, the Atlantic brief squid, or Lolliguncula brevis, stands out as an exception. This small species of squid in the Loliginidae family demonstrates remarkable adaptability, tolerating low salinities and thriving across a wide a wide range of environmental conditions, commonly found swimming in shallow waters of the western Atlantic Ocean. Such adaptability holds considerable value, especially amid the diverse environmental changes driven by climate change. However, our current understanding of the distribution of L. brevis remains limited.

Our objective is to enhance our understanding of the spatial and temporal distribution patterns of the Atlantic brief squid in response to changing environmental conditions over a thirty-year period from 1989 to 2019. We gathered existing data from NOAA DisMAP to map the known distribution range of the Atlantic brief squid along the Southeast United States coastline.

Dataset Information

[Table 1] Dataset Information
Detail Description
Data Source NOAA Distribution Mapping and Analysis Portal (DisMAP)
Item Atlantic Brief Squid (Lolliguncula brevis) in Southeast US, Fall & Spring & Summer
Retrieved From https://apps-st.fisheries.noaa.gov/dismap/DisMAP.html
Variable Used Lattitude, Longitude, Depth, Year, Weight Catch per unit Effort, Season
Data Range 1989~2019

Our data was sourced from NOAA Distribution Mapping and Analysis Portal (DisMAP), an interactive platform that contains geographical and numerical visualization of several key metrics defining the range and distribution of individual species over time. The raw data were collected by the National Marine Fisheries Service of the National Oceanic and Atmospheric Administration during annual bottom trawl fisheries surveys. We specifically focused on the Atlantic brief squid (Lolliguncula brevis) as the species of interest, within the Southeast US as the study area, NMFS/Rutgers IDW Interpolation as study model/distribution project, and then obtained survey points data for the fall, spring, and summer seasons.

Exploratory Analysis

Table

[Table 2] Statistical Summary of Variables, Depth, WTCPUE, Latitude
Mean Median Max Min Skewness
Depth 8.05 8.00 13.00 2.00 -0.22
WTCPUE 0.25 0.15 6.55 0.00 5.21
Latitude 32.17 32.40 35.23 28.76 -0.25
[Table 3] Statistical Summary of WTCPUE by Year
Year Observations Mean Median Max Min Skewness
1989 126 0.36 0.20 2.57 0 2.06
1990 201 0.25 0.17 4.81 0 7.36
1991 198 0.36 0.21 6.15 0 5.60
1992 160 0.22 0.11 3.02 0 4.29
1993 191 0.17 0.12 1.28 0 2.41
1994 193 0.24 0.14 1.90 0 2.21
1995 205 0.20 0.13 1.22 0 1.51
1996 212 0.27 0.21 1.45 0 1.53
1997 174 0.25 0.13 2.17 0 2.55
1998 208 0.30 0.18 4.85 0 5.82
1999 194 0.27 0.20 1.77 0 2.28
2000 188 0.21 0.17 2.27 0 4.29
2001 240 0.22 0.14 2.06 0 3.11
2002 230 0.23 0.13 2.70 0 3.38
2003 256 0.22 0.13 1.74 0 2.42
2004 242 0.33 0.22 6.55 0 7.65
2005 253 0.26 0.16 4.31 0 6.44
2006 223 0.19 0.11 1.47 0 2.42
2007 217 0.29 0.12 2.90 0 2.44
2008 266 0.26 0.15 3.88 0 4.53
2009 266 0.20 0.12 2.48 0 4.06
2010 284 0.19 0.12 1.43 0 2.51
2011 276 0.35 0.22 4.13 0 3.60
2012 241 0.19 0.12 1.39 0 2.32
2013 256 0.23 0.15 2.62 0 3.63
2014 226 0.14 0.08 1.80 0 4.20
2015 242 0.26 0.17 1.68 0 1.59
2016 279 0.30 0.18 2.02 0 2.03
2017 247 0.39 0.19 3.34 0 2.89
2018 145 0.22 0.16 1.42 0 2.38
2019 139 0.18 0.10 1.45 0 2.39
[Table 4] Statistical Summary of WTCPUE by Season
Season Observations Mean Median Max Min Skewness
Fall 2224 0.31 0.19 6.55 0 4.99
Spring 2170 0.19 0.12 2.17 0 2.57
Summer 2384 0.26 0.15 6.15 0 4.69

Graphing Change in Latitude

3. Maping

Analysis

1. Depth ~ Year

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2. wtcpue ~ depth

3. wtcpue ~ year

4. wtcpue ~ season

ONE-WAY ANOVA test

Null Hypothesis: There are no differences in the means of wtcpue among seasons. Alternative Hypothesis: There are differences in the means of wtcpue among seasons.

Based on the result of the one-way ANOVA test: the test statistic (F value) is 73.44; the p-value associated with the test is very small (approximately < 2e-16), indicating strong evidence against the null hypothesis. Therefore, we reject the null hypothesis and conclude that there are significant differences in the means of wtcpue among seasons. This suggests that season has a significant effect on the weight catch per unit effort, implying that seasonal changes, including factors like temperature, moisture, and currents, potentially influence the squid population and biomass.

Summary and Conclusions

References

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